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HD3SS3220: Controller behavior with no I2C communication

John Monaghan
Prodigy 20 points
Part Number: HD3SS3220
Other Parts Discussed in Thread: TPS25910, TPS2597, TPS25981

For HD3SS3220:

I need to use the chip as a Type A to Type C converter (port controller), in one design as an US port, and in another as a DS port. I need this to occur without external processor interaction, as my design has no dedicated processor for controlling the USB port.

1. Does this chip require any communication over I2C to begin operating as a DS or US port controller? Some other companies market their type-C port controllers as "autonomous", meaning they can operate as port controllers with just pin configurations, and not requiring any processor control.

2. What added functionality does the I2C communication provide?

3. What is the off-the-shelf or "out-of-the-box" behavior of the chip, with no communication occurring or register changes occurring over the I2C bus.

3. Are any registers One-Time-Programmable?

  • 0
    TI__Guru**** 176721 points

    Hi,

    1. You can configure the HD3SS3220 using pin-strap configuration. Please note for DFP, the VBUS needs to be off until the CC handshake is completed. So you can use the ID pin to control the VBUS voltage regulator.

    2. The use of I2C is optional but strongly encouraged. It is recommend to understand in more detail what is connected to the Type-C port. This is more relevant to detection audio accessories and debug accessories. Also some other features listed below are lost without I2C:

    • ACTIVE CABL E DETECTION
    • DRP Duty cycle control
    • Disable UFP accessory support
      • Can be important for compliance testing

    • Selection of Try.SRC or Try.SNK.

    3. The registers can be programmed continuously, but will revert back to its default value when there is a power cycle.

    Thanks
    David

  • 0 in reply to David (ASIC) Liu
    Prodigy 20 points

    thanks.

    1. For DS facing port: I see in the datasheet that the 'ID pin is asserted low when CC detects a device attachment': 

    1.a) How does that relate to the CC handshake? Is a device considered "attached" before or after a handshake?

    1.b) During CC handshake what is the logic level of the ID pin and what is it after the handshake?

    1.c) The eval board for this chip has TPS25910, which has an enable_not pin (EN#) - so it is inverted enable logic. Will things work correctly if I use a VBus switch that instead has non-inverted enable logic, combined with an inverter chip in front of it?

    2. ok

    3. ok

    4. (3.) ok 

  • 0 in reply to John Monaghan
    TI__Guru**** 176721 points

    Hi,

    A DFP monitors the voltage level on the CC pins looking for the R(d) termination of a UFP. When a UFP is detected and HD3SS3220 is in the attached.SRC state, the HD3SS3220 pulls the ID pin low to indicate to the system the port is attached to a device (UFP).

    The TPS25910 EN is an active low signal, so you can connect directly the ID pin to the EN pin so once the HD3SS322 in in the attached.SRC state, the VBUS will be turned on. You do not need additional external inverter.

    Thanks

    David

  • 0 in reply to David (ASIC) Liu
    Prodigy 20 points

    Thanks. I am unable to source TPS25910.

    Can you recommend an alternative to TPS25910?

    The question about the inverter is for a possible alternative to TPS25910 that I can source, but this alternative (MIC2039AYMT - active high) enables its VBUS output on active high signal. So will think things will work correctly if I add an inverter before the MIC2039?

  • 0 in reply to John Monaghan
    TI__Guru* 79181 points

    Hi John,

    Please have a look at TPS2597, TPS25981. How much voltage and current you need? 

    Regards

    Kunal Goel